This invention relates to improved resinous textured sheets of the general type of the known chemically embossed foamed thermoplastic resin sheets used in floor coverings, wall coverings, counter tops, upholstery, drapes and the like.
Chemically embossed thermoplastic resin sheets have been disclosed extensively in the prior art, for example in U.S. Pat. No. 3,293,094 of Dec. 20, 1966 to Nairn et al. for "Textured Foam Process". This patent discloses a number of variants of a process wherein a layer of foamable thermoplastic composition, comprising a chemical blowing agent and a plastisol, organosol, latex, or dry blend contacts over limited areas a foaming inhibitor, i.e., a chemical inhibitor or accelerator of decomposition of the blowing agent. The inhibitor prevents foaming of the foamable thermoplastic composition in the areas of the sheet where it is present, under conditions which allow foaming of the rest of the foamable composition; either by preventing decomposition of the blowing agent in contact therewith, or by accelerating such decomposition to the point that excessive pressure develops in the areas where foam is in contact with such decomposition accelerator and the foam consequently collapses in those areas. See Nairn et al. col. 13, line 59--col. 19, line 56.
Nairn et al. discloses that the foaming inhibitor can be in contact with the upper surface of the foamable layer containing blowing agent, or can contact the foamable layer from immediately below. See Nairn et al. at col. 4, lines 21-70. The pattern imposed by printing on the foamable layer with an inhibitor composition can be an exact reproducible design, or can be random. See Nairn et al. at col. 5, lines 29-31.
Nairn et al. sets forth numerous specific examples disclosing foamable plastisol compositions comprising thermoplastic resin, plasticizer, and blowing agent; and disclosing various chemical foaming inhibitors therefor. (Examples 1-81).
Also of possible pertinence is U.S. Pat. No. 4,278,483 of July 14, 1981 to R. D. Mansolillo for disclosure of dry blend granules deposited on a base sheet and sintered to form a porous mass; which dry blend is prepared from calender grade resin, especially PVC, and plasticizer and stabilizer. See col. 7, line 14--col. 8, line 33 and Example I. A mixture of dry blend and plasticizer is printed, e.g., using a silk screen, onto specific areas of the porous sintered layer in a design. An excess of the printing composition over that needed to fill the voids in the sintered layer below the printed areas is supplied; with the result that the printed areas are higher than the unprinted areas. The sheet is then consolidated by heat. See col. 2, lines 41-68; and col. 10, lines 39-51. A blowing agent can be included in the printing composition to enhance the textured appearance by forming a cellular composition when heated. See col. 10, line 52--col. 11, line 6.